Determination of total antimony and antimony(V) by inductively coupled plasma mass spectrometry after selective separation of antimony(III) by solvent extraction with N-benzoyl-N-phenylhydroxylamine

The study of antimony speciation in various types of natural water from the area of Warsaw city was performed. For this purpose the simple, fast and specific analytical method of determination of total inorganic antimony and antimony(V) in aqueous phase of the sample by inductively coupled plasma mass spectrometry (ICP-MS) was developed. The procedure is based on selective removal of antimony(III) by solvent extraction with N-benzoyl-N-phenylhydroxylamine. The concentration of Sb(III) was calculated as a difference between total antimony and Sb(V) concentrations. The detection limit achieved by described procedure in combination with ICP-MS detection was 0.7 ng l−1. The relative standard deviations for analysis of three samples containing 0.028–0.915 μg l−1 of total antimony and 0.027–0.894 μg l−1 of Sb(V) ranged from 0.46 to 2.9% and 0.60 to 3.7%, respectively. The antimony concentration in all samples analyzed was less than 1 μg l−1. Speciation studies revealed that in natural waters the prevailing chemical form is antimony(V). The on-field separation of both forms of antimony assures stabilization of speciation at the site of sampling.